Vancomycin and tetracycline-resistant enterococci from from raw and processed meats: phenotypic and genotypic characteristics of isolates

Abstract

The ubiquitous nature of enterococci and their ability to colonize different habitats account for their easy spread throughout the food chain. Here, we evaluated the distribution and antimicrobial susceptibility of Enterococcus isolates from meats obtained from different supermarkets. We acquired and cultured 100 products (raw chicken meat, raw pork, and boiled meats) to screen for the presence of Enterococcus spp. In total, 194 isolates were recovered from the samples, with contamination rates of 63.6% in the chicken samples, 31% in the raw pork meat, and 1.4% in the boiled meat samples. PCR amplification with specific primers was performed to screen the DNA of Enterococcus spp. (95/96), E. faecalis (66/96), E. faecium (30/96), and E. casseliflavus/E. flavescens (3/96). The antimicrobial susceptibility tests showed that all the isolates were resistant to at least one of the antibiotics. All E. faecium isolates were resistant to vancomycin, streptomycin, ciprofloxacin, norfloxacin, erythromycin, and tetracycline. The E. casseliflavus/E. flavescens isolates were resistant to gentamicin, streptomycin, ciprofloxacin, norfloxacin, erythromycin, and tetracycline. E. faecalis isolates were resistant to ciprofloxacin, tetracycline, and erythromycin (92%), norfloxacin (83%), vancomycin, and streptomycin (50%). The resistance genes tetL and vanB were detected by genotyping. The presence of these antimicrobial-resistant microorganisms in food might pose problems for public health.
Keywords: Antimicrobials, PCR, vancomycin-resistant enterococci